Concentration-Dependent Effects of Magnesium Ions on Thermal Denaturation Kinetics of Hen Egg-White Lysozyme: a Raman Spectroscopic Study

Although abnormal magnesium levels (Mg²⁺) are associated with various neurodegenerative diseases, their effects on denaturation kinetics of proteins at the molecular level remain poorly understood. In this study, using hen egg-white lysozyme (HEWL) as a model system, we investigated the influence of magnesium ions on thermal denaturation kinetics of HEWL in the absence of acid or mechanical agitation. By employing Raman spectroscopy and monitoring changes in protein secondary and tertiary structures using well-known Raman indicators, we observed that Mg²⁺ ions have a minimal impact on the unfolding of tertiary structures. In contrast, at high concentrations, Mg²⁺ significantly promotes the transformation of α-helical structures into β-sheet-like structures. Furthermore, compared to Zn²⁺ ions, Mg²⁺ exhibits a weaker effect on the secondary structure transition. These findings underscore the concentration-dependent role of Mg²⁺ in modulating the thermal denaturation of HEWL, providing new insights into the molecular mechanisms by which metal ions influence amyloid fibrillation.